Field of the Invention
The present invention relates to mobile communications.
Related Art
3GPP 3rd Generation Partnership Project LTE Long Term Evolution that is an advancement of UMTS Universal Mobile Telecommunication System is being introduced with 3GPP release 8. In 3GPP LTE, OFDMA orthogonal frequency division multiple access is used for downlink, and SC-FDMA single carrier-frequency division multiple access is used for uplink. Further, in order to cope with a rapidly increasing data traffic in 3GPP LTE-A LTE-Advanced as an evolution of 3GPP LTE, carrier aggregation CA has been introduced which may aggregate up to five carriers.
On the other hand, D2D communications device-to-device communication may be a distributed communications technique where data traffics are communicated between adjacent wireless nodes. In the D2D communications, a wireless node such as a mobile phone may search for another physically adjacent wireless node on its own, and, if there is a physically adjacent wireless node, may set a communications session, and then, may send the data traffic to the physically adjacent wireless node. As the D2D communications, Bluetooth or WiFi Direct may support direct communications between the wireless nodes without use of a base station. Further, the D2D communications may be possible where scheduling for the D2D communications may be managed by a base station. Such D2D communications managed by the base station may distribute data traffics which otherwise be concentrated on the base station, to reduce traffic overloads.
However, the LTE/LTE-A based cellular communications and D2D communications between the wireless nodes may interfere with each other.